Apatite Induced Renal Epithelial Injury: Insight Into the Pathogenesis of Kidney Stones

Carla Escobar, Karen J. Byer, Hassan Khaskheli, Saeed R. Khan

Research output: Contribution to journalArticle

Abstract

Purpose: Kidney stone formation is associated with the deposition of hydroxyapatite as subepithelial plaques or tubular deposits in the renal papillae. We investigated the effect of renal epithelial exposure to hydroxyapatite crystals in vitro to develop an insight into the pathogenesis of kidney stones. Materials and Methods: NRK52E cells (No. CRL-1571, ATCC®) were exposed to 67 or 133 μg/cm2 hydroxyapatite (No. 21223, Sigma-Aldrich™) or calcium oxalate monohydrate crystals (No. 27609, BDH Industries, Poole, United Kingdom). In some studies cells were also exposed to crystals from the basal side. After 3 or 6 hours of exposure medium was analyzed for lactate dehydrogenase, 8-isoprostane and H2O2. Medium collected after cell exposure on the apical side was also analyzed for the production of monocyte chemoattractant protein-1 and prostaglandin E2. Cells were stained with DAPI to determine apoptotic activity and examined by scanning electron microscopy to observe crystal-cell interaction. Results: Cell exposure to hydroxyapatite resulted in H2O2 and 8-isoprostane production as well as in lactate dehydrogenase release. Apical exposure appeared more provocative and injurious than basal exposure. Exposure to hydroxyapatite for 6 hours resulted in increased apoptotic activity. Apical exposure also resulted in increased monocyte chemoattractant protein-1 and prostaglandin E2 production. Conclusions: Cell exposure to hydroxyapatite crystals induced oxidative stress and lipid peroxidation. It caused up-regulation of the inflammation mediators that may be responsible for the kidney inflammation in patients with stones that is associated with tubular hydroxyapatite deposition. It may also have a role in the eruption of subepithelial Randall's plaques to the papillary surface.

Original languageEnglish (US)
Pages (from-to)379-387
Number of pages9
JournalJournal of Urology
Volume180
Issue number1
DOIs
StatePublished - Jul 2008
Externally publishedYes

Keywords

  • apatites
  • inflammation
  • kidney
  • kidney calculi
  • reactive oxygen species

ASJC Scopus subject areas

  • Urology

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